percpu-rwsem: Replace synchronize_sched() with synchronize_rcu() (e3e74054) · Commits · 戴 / test

Now that synchronize_rcu() waits for preempt-disable regions of code as well as RCU read-side critical sections, synchronize_sched() can be replaced by synchronize_rcu(). This commit therefore makes this change, even though it is but a comment. Signed-off-by:

Paul E. McKenney <paulmck@linux.ibm.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Christoph Lameter <cl@linux.com> Acked-by:

Tejun Heo <tj@kernel.org>

include/linux/percpu-rwsem.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -41,7 +41,7 @@ static inline void percpu_down_read_preempt_disable(struct percpu_rw_semaphore *
		* cannot both change sem->state from readers_fast and start checking
		* counters while we are here. So if we see !sem->state, we know that
		* the writer won't be checking until we're past the preempt_enable()
		* and that one the synchronize_sched() is done, the writer will see
		* and that once the synchronize_rcu() is done, the writer will see
		* anything we did within this RCU-sched read-size critical section.
		*/
		__this_cpu_inc(*sem->read_count);

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